Austin Texas Thermal Expansion coefficients

[Gustatorian]

Anybody happen to know the thermal expansion coefficients for boiling temps and mash out temps for Austin Texas. I know people universally use 4% for boiling, but I'm looking for numbers that are a bit more specific.

 

[morbster]

Your best bet may be to test it yourself with a large graduated cylinder.

IMO, 4% is a good approximation since you're near sea level.

 

[Btaz]

Boiling water temp at elevation
http://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html

 

[Btaz]

I did some curve fits to some wort expansion data and came up with an equation. I'll have to dig it up for you

 

[Dcpcooks]

Your best off measuring your own data on your gear at your location.

 

[doug293cz]

Boiling temp changes with altitude, but thermal expansion vs. temp does not change measurably. You can find a table of values for water at the Engineering Toolbox (linked in a earlier post.) If you want more accurate thermal expansion as a function of wort concentration and temp, check out this thread, starting at post #17.

Brew on

 

[Btaz]

Here is the simple thing I used. Data comes from www.biabrewer.info from there I ended up with the following polynomial y =*3.63679198*10^-6*x^2*+ 7.515789474*10^-5*x*+ 9.995432907*10^-1 were y is wort expansion % and x is degrees C

[6/14: updated y meaning]

 

[pricelessbrewing]

Boiling temp changes with altitude, but thermal expansion vs. temp does not change measurably. You can find a table of values for water at the Engineering Toolbox (linked in a earlier post.) If you want more accurate thermal expansion as a function of wort concentration and temp, check out this thread, starting at post #17.

Brew on

Did you ever finish that one doug? How much difference did it end up being vs water vs treating it as a succrose solution?

 

[NoIguanaForZ]

Fair question: is the difference in thermal expansion really to be larger than the range of error in your volume measurements?

 

[doug293cz]

Did you ever finish that one doug? How much difference did it end up being vs water vs treating it as a succrose solution?

No, just one of several things I haven't finished yet.

Brew on

 

[doug293cz]

Fair question: is the difference in thermal expansion really to be larger than the range of error in your volume measurements?

Probably not, but won't know until I finish the analysis, or someone else who has done the analysis already speaks up.

It's a good question though. I went to great lengths to build a mash/sparge simulator that uses a very rigorous mass balance method. It was fun to do, and playing with it over time has given me lots of insights into lautering processes. @pricelessbrewing adopted my simulator math for his on-line calculator. Then he did some additional analysis, and found that the error of using the simple gravity point method is much less than the error in the volume and SG measurements used as inputs. So, the simpler method is more than adequate for the task. The rigorous method is really overkill for homebrewing, but the learning was worth it.

Brew on